Question

Dada a figura, Calcule o valor de x

Answer 1

$\mathrm{Perceba\ que\ x\ \acute{e}\ o\ cateto\ adjascente\ ao\ \hat{a}ngulo\ de\ 60\º,}\\ \mathrm{e\ o\ lado\ de\ 12\ cm\ \acute{e}\ a\ hipotenusa\ do\ tri\hat{a}ngulo.\ Logo,}\\ \textrm{podemos utilizar a rela\c{c}\~{a}o\ \textbf{cosseno}.}\\\\ \mathrm{\cos{\theta}=\dfrac{cateto\ adjascente}{hipotenusa}\ \to\ \cos{60\º}=\dfrac{x}{12}}\\\\ \mathrm{x=12\cos{60\º}\ \to\ x=12.\dfrac{1}{2}\ \to\ \boxed{\mathbf{x=6\ cm}}}$